Construction of trestle-bridges.



No. 666,833. Patented Ian-.129, |90l.

.v F. WELDON. CUNSTBUGTION 0F T BESTLE BRIDGES.

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. No. 666,833. Patented lan. 29, I90I.

. F. WELDUN.

CONSTRUCTION 0F TRESTLE BRIDGES.

(Application sied-my 1o, moo.)

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No. 666,833. Patented Jan. 29, I90l. F. WELDUN.

CONSTRUCTION 0F TRESTLE BRIDGES. v fAppucazioA mea my' 19, 1900.)

(No Model.) y 5 Sheets-Sheet 4.

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(Application led my 19, 1900.)

Patented lan. 29, |90I.

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UNITED STATES v FFICE.D

PATENT CONSTRUCTION OF TRESTLE-BRIDG ES.

SPECIFICATION forming part of Letters Patent No. 666,833, dated January 29, 1901.

Application filed May' 19, 1900. Serial N0. 17.205- (NO model.)

To @ZZ whom it may concern/z A Be it known that I, FRANCIS WELDON, a subject of the Queen of Great Britain and Ireland, residing at Earley, Reading, 'in the county of Berks, England, have invented Improvements in the Construction of Trestle- Bridges for Military and other Purposes, of which the following is a specification.

My invention has for its object to enable 1o temporary bridges to be readily constructed with their roadways practically horizontal in a transverse sense notwithstanding differences in the levels of the parts of river-beds or other surfaces or foundations upon or in which rest the various vertical or nearly vertical supports that carry such roadways or the unequal sinking of the said supports therein. For this purpose in a bridge according to my invention the roadway is carried by transoms adzo jnstably secured by wire ropes or chains to vertical or nearly vertical supports, which are tied together by ledgers, and other transoms and diagonal ropes or chains which are independent of the road-carrying transoms, so that if the bed or surface upon which the supports rest be uneven or if, owing to the Acharacter of the surface, some of the supports sink into the earth and others do not or some sink more than others the road-transoms (which are 3o preferably secured to the uprights after the latter, tied together as stated, have been put into place) can be easily adjusted so as nevertheless to be horizontal, while the ledger and the transom which constitute each pair and 3 5 which are lashed with chains or wire ropes to the supports will remain approximately parallel to each other, and the diagonal ties can be easily adjusted so as to cause the supports to maintain or to assume and maintain their 4o proper vertical or nearly vertical positions.

Figures l to 6, inclusive, of the accompanying drawings represent an example of a bridge constructed according to this invention. Fig. l is a perspective View of a portion thereof.

Figs. 2, 3, and 4 are sections thereof corresponding, respectively, to the lines II of Fig. 3, III of Fig. 2, and IV of Fig. 3; and Figs. 5 and 6 are respectively front and rear elevations representing the means employed for 5o adj ustably securing a road-transom to a support. Fig. 7 is an end view showing a modification of the means shown in Figs. 5 and 6 for securing a road-transom to a support.

In the example shown each of the supports d, to which the road-transoms are secured, is for ease in transport constructed of three comparatively light wooden poles, which are lashed together at intervals and two of which bear against the corresponding road-transoin. Metal poles may, however, be used in lieu of 6o' wooden ones and then some softer material, as a piece of wood or a layer of pitch, may be interposed between the transom and the support to increase the friction. The supports a, are arranged in pairs, and each pair of supports isl tied together by a ledger b, a transom c, and diagonal chains Cl, provided wi th chain stay-tighteners e to form a trestleframe, to the supports at of which a roadtransom fis adjustably secured, as hereinaf- 7o ter described. The two supports a of each trestle-frame may be somewhat wider apart at the bottom than the top, so as to give a Wider base to the bridge. Each road-transom f comprises, as shown in Fig. 4, ive boards-viz. two outer pairs of boards placed end to end and an inner board-bolted together. The two end bolts g g project on each side and have attached to them two chains h, between which and the said boards are 8o forced two blocks la, so as to form a trussed girder. In the example the road-transomf extends beyond the supports a, the overhanging extension Z forming cantalivers, whose outer ends may be supported by chain-loops m from hand-rails n, adjustably secured to supplementary vertical or nearly vertical slipports p.

There may be any required number of supports a to carry one road-transom f, and for 9o tying together the supports constituting a set more than one transom c, besides the roadtransom f, may be used in addition to the ledger b. The number of diagonals d will likewise depend upon circumstances.

The road-transoms f are adj ustably secured to the supports a by wire ropes or chains r, Figs. 5 and 6, each passed half around the support a below the road-transom f, then upward outside the transom f, so as to hold it against the support, and then entirely around the support one or more times above the IOO transom, where the free ends of the wire rope or chain are suitably secured together by a hook and loop or eye or equivalent fasteningpreferably by a hook s secured to one end of the chain, passed through a ring secured to the other end, and then carried back and placed in the first convenient link of its own end that presents itself. The full weight of the transom is then allowed to fall on the supporting-loop thus formed, and the portion of the chain passed half around the support a is hammered down at the side thereof away from the transom, so as to be level, as shown. When the transom has thus been secured to both of the supports a, it is vstruck downward repeatedly with a heavy maul or mallet until the maul or mallet rebounds from the transom as if the structure were solid. To prevent the chain r from slipping down on the supports a, a staple may be partially hammered in over the upmost convolution of the chain.v In order to adjust the transom, the staple, if used, must be removed and a smart upward blow given to the lower edge of the transom to disengage it from vthe surface of the support a. A block of wood t may in some cases, as shown in Fig. 7, be inserted between the transom f and cach chain fr totprevent the weakening of the ytransom by the cutting in of the chain. The other transoms c, the ledgers b, and the hand-rails n may be fastened to the supports a either in the same way as the road-transoms or in any other suitable manner. The supports may be shod where requisite.

In some cases it may be advantageous to introduce one or more props u between a roadtransom and transom below it, as shown in Fig. 3.

In building a bridge according to this invention the operation is preferably as follows: The site being decided upon, each trestleframe as it is made is floated out on a raft to its ,predetermined position, upon reaching which it is up-ended while resting on a rail supported at one side of the raft and lowered gradually. Vhen its two supports are grounded, the diagonal ties d are, if necessary, adjusted by means of the stay-tighteners e, so as to bring the supports ct into their proper position. A balk is now run out from the bank or from the transom c of the trestle-frame last laid, and secured to the transom c of the new trestle-frame, so as to form a temporary level platform for the conveyance of the road-transom, which is now attached to the two supports a in the manner described with reference to Figs. 5 and 6. Balks w are now run out from the bank upon the road-transom of the last previously vlaid trestle-frame and secured to the road-transom of the new trestle-frame, the temporary platform removed from the transoms, and the chesses laid across the balks w. After all the trestle-frames have been treated as described they are secured to one 'another by means of a number of chains or ropes y, Fig.

2, each of which is secured at one end z to the upper end of a support a and at the other end l to the same support @lower down, and each of which is connected either to another chain or rope y on the next support by other chains or ropes 2, screwed together by means of a stay-tightener 3, or by chains or ropes 4 and a stay-tightener 5 to a pole, firmly driven into the ground.

l. In a temporary bridge, the combination of a trestle-fraine comprising vertical or nearly vertical supports, a ledger, a frame-transom, and adjustable diagonals connecting the said supports together, and a road-transom Secured to and adjustable on the said supports independently of the said ledger, frame-transom, and diagonals, substantially as and for the purpose set forth.

2. In a temporary bridge, the combination of a trestle-frame comprisingvertical or nearly vertical supports, a ledger, a frame-transom, and adjustable diagonale, a roadtransom secured to the said supports independently of the said ledger, frame-transom, and diagonals, and a prop or props between the said road-transom and the said frametransom.

3. In a temporary bridge, the combination of a trestle-frame comprising a vertical or nearly vertical support, a stay chain or rope connected to parts of the said support at different heights, and another chain or rope attached intermediately to the said stay chain or rope and adapted to connect it to a corresponding stay chain or rope of an adjacent trestle-frame or to a fixture secured independently of the bridge.

1l. In a temporary bridge, the combination of a trestle-frame comprising a vertical or nearly vertical support, a stay chain or rope connected to parts of the said support at different heights, and a connection comprising another chain or rope and a stay-tightener, attached intermediately to the said stay chain or rope, and adapted to connect it toa corresponding stay chain or rope of an adjacent trestle-frame or to a fixture secured independently of the bridge, substantially as and for the purpose set forth.

5. In a temporary bridge, the combination of a trestle frame comprising vertical or nearly vertical supports, a ledger, a frametransom,and adjustable diagonals connecting the said supports together, and a road-transom secured to and adjustable on the said supports independently of the said ledger, frametransom, and diagonals, and comprising cantalivers extending beyond the saidsupports, substantially as and for the purposes set forth.

6. In a temporary bridge, the combination of a trestleframe .comprising vertical or nearly vertical supports, a ledger, a frametransom,and adjustable diagonals connecting the said supports together, and a road-transom secured to and adjustable on the said'su pports independently of the said ledger, frame- IOO IOS

IIO

transom, and diagonale, and comprising eantalivers extending beyond the said supports, means for supporting the outer ends of the said cantalivers, substantially as and for the purposes set forth.

7. In a temporary bridge, the Combination of a trestle frame comprising vertical or nearly Vertical supports, a ledger, a frametransom,and adjustable diagonals connecting the said supports together, and a road-transom sec u red to and adjustable on the said supports independently of the said ledger, frametransom, and diagonals, and comprising cantalivers extending beyond the said supports, supplementary vertical or nearly vertical supports, hand-rails adjustably secured to the last-mentioned supports, and means for carrying the outer ends of the said eantalivers from the said supplementary supports, substantially as and for the purposes set forth. Signed at 4 Lineolns Inn Fields, London, E. C., England, this 3d day of May, 1900.

FRANCIS WELDON.

Witnesses: Y

JOHN ARTHUR LAW, WILLIAM HENRY SIMMS. 

